1. Field of the Invention
The invention relates generally to polytetraflouroethylene (PTFE) seals for use in dynamic shaft seal applications and the like where a PTFE wafer is used as a seal component and a method of fabrication therefor.
2. Related Art
The art of producing effective seals between a rotating member and a stationary member is under continual development. It is well know that seals acting between a rotating member and a stationary member often comprise a PTFE component in combination with an elastomer component. The manufacture of the PTFE seal component is typically the bottleneck in the process of producing a seal. PTFE is difficult to form to a desired shape due to its inherent heat resistant characteristics, and thus, poor conductivity. This makes PTFE difficult to mold, thus complicating the manufacture process of making components parts from PTFE.
Typically, PTFE is formed to the desired component geometry by exposing PTFE resin powder to melting temperatures, in the desired mold geometry, for an extended period of time. The amount of time required to process the PTFE resin powder from a “green” state to a cured or sintered state can take anywhere between 2 to 10 hours or more, depending on the geometry sought. This amount of time investment to produce a component for a seal is highly cost inefficient from the standpoint of labor, energy consumption, and space consumption in a furnace, among other associated costs. Additionally, the interruption of the manufacture process to produce a seal by having to spend so much time in a single operation, i.e. sintering of the PTFE seal element, prevents manufacturing efficiencies otherwise possible by utilizing a continuous manufacturing process.
Therefore, being as many seals in production today utilize a PTFE component for its lubricious properties, it would be highly advantageous to have a process for construction a PTFE seal component in an efficient manner. A method of constructing a PTFE seal component according to the current invention as described hereafter in a currently preferred embodiment of the invention overcomes or greatly minimizes the limitations of prior methods of forming a seal component manufactured from PTFE.